In line with its global commitments, the government has set a target to increase India’s renewable energy capacity by 175 gigawatts (GW) by 2022.

The energy sector has responded quickly. In 2018, India added a net total of 17.6GW of power generation capacity, a record 74% of which was based on renewable energy technologies – primarily solar power.

This ongoing drive for clean energy and the falling cost of wind and solar technologies has shaken coal power’s dominance in the sector and created increasing uncertainty in the market.

Thermal power companies have also had to respond. NTPC, for example, has scrapped plans for several large coal projects, including one for a 4GW plant in southern Andhra Pradesh state.

“For the overall power mix renewables are posing big competition; solar is growing in capacity additions and coal has started to decline,” says Singh.

However, he notes that while thermal power companies are under pressure, co-firing is not counted as renewable capacity in India, so though good, it is not necessarily an obvious choice for coal power companies.

“There is also a slightly higher cost related to doing this; they need to make slight technical changes to the boilers, and biomass pellets cost more than coal, there will also be an increase in the power consumption and heat rate in the plant,” he explains.

“However, to compensate for these additional costs, the regulator has allowed NTPC to pass them on to the consumer, otherwise there would have been little incentive to use biomass,” says Singh.

Nevertheless, as Patricia Thornley, director of European Bioenergy Research Industry at Aston University in the UK, points out, co-firing is a quick and relatively painless way to reduce coal-fired power plant emissions.

“One of the really attractive things about biomass coal-firing is that it is a really cheap, low-capital cost way of getting renewable capacity in the electricity generating sector,” she says.

“What we have seen happen in other countries – the UK and across Europe, for example – is because the infrastructure of the coal-fired power plant is just sitting there, it is relatively easy to adjust the plant to deal with up to 20% biomass,” she explains.

In some cases, like in the UK, this has resulted in power companies increasing the amount of biomass they use, with Drax deciding to switch completely to biomass.

Thornley says that for the overall carbon production of electricity, co-firing in coal power plants reduces the carbon emissions by around 90% for the biomass part compared to the coal part.

The big question, however, is where does the biomass come from?

“There are issues if there is land use change or a big carbon release associated with biomass, which can affect the carbon saving,” she explains.

As noted, NTPC is trying to build a sustainable supply chain for biomass from local farmers already burning their crop residue and has invited expressions of interest for them to supply this, says Singh, after which the company will hold a workshop and select the vendors.

Although a significant step in the right direction, NTPC’s announcement is not going to have a huge impact on India’s overall energy mix, according to Singh.

Current coal-based emission capacity is close to 400GW and the current biomass capacity is only 10,000MW, he says.

“NTPC’s coal-based capacity is close to 40GW, if all of their plants start using 5% co-firing with biomass, it only amounts to 2GW; however, it will have a positive impact by reducing pollution in specific clusters around the country, such as near Deli,” Singh explains.

If all NTPC’s power stations use 5% biomass, they will use around 7-8 million tons per annum (Mtpa). Singh estimates overall biomass produced in the country is around 500Mt, most of which goes into animal products. This means there is a surplus of around 145Mt, 35-45Mt of which is burned.

Therefore, there is plenty of capacity for more coal-fired power companies to follow NTPC’s lead, which could be where the real environmental gains and energy mix impacts are made eventually.

“If all the other coal-fired power plants start co-firing with biomass, then definitely more biomass will get utilised,” he says. “On the around 200GW of coal-fired generation that currently exists, if all start utilising biomass for 5%, that will be around 20-28Mt of biomass, which would be quite significant – but we don’t know whether and when this will happen.”